Ottawa Riverkeeper raises concerns over winter road salt use

Salt is a common sight on roads, sidewalks and stairs in Ottawa every winter, but the Ottawa Riverkeeper is urging residents to cut back on their use of road salt because of the effect it has on rivers and streams.

The Riverkeeper monitored 30 streams over the last four years and said that 90 per cent of those sites routinely saw levels of contamination from salt that can cause harm to freshwater species.

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"What we're finding, through five winters of monitoring for chloride levels, is that they are shockingly high," Ottawa Riverkeeper CEO Laura Reinsborough told CTV News at Noon.

"We're testing creeks and streams in Ottawa and Gatineau and over 90 per cent of those that we're testing are having acute and chronic toxicity. We know that road salt can be toxic when it reaches water and if it gets to that high level, it causes problems for all of the aquatic organisms."

Reinsborough said monitoring has found an amount of salt that is 200 times the acceptable level in some waterways.

"We also studied the levels into the summer and they stayed high," she said. "The chloride ions from the road salt will actually embed in the mud and they'll stay there."

Reinsborough says salt is often overused in the winter.

According to the Ottawa Riverkeeper's website, using salt for traction is wrong.

"Salt is not intended for grit or traction. If you are spreading more and more salt, without waiting for it to dissolve, so that you can walk on the crystals and have a grip on the ice, you are using salt incorrectly," the Riverkeeper says. "Instead, reach for a product like sand or gravel to provide a layer of traction between your boot and the ice. Plus, at the end of the season, you can sweep up the remaining gravel and use it again the following year, saving money and helping the environment."

Salt also stops working to dissolve ice once it gets colder than -10 C.

One of the best tips, Reinsborough says, is to simply use less salt.

"Think about a two-car wide driveway. One coffee mug of road salt is enough for that entire surface area," she said.

"For each square metre of surface area, you only need two tablespoons of salt. Put another way, that’s roughly eight tablespoons of salt per standard sidewalk square in the City of Ottawa," the Riverkeeper's website says.

The Riverkeeper says excessive road salt use is a solvable problem.

"While municipalities and private companies need to tackle this issue at a large scale, there is much you can do as an individual to reduce road salt use," it says.

The City of Ottawa says it uses a variety of materials in winter operations to maintain driveable roads.

"The City of Ottawa is an early adopter of salt management best practices to minimize environmental impacts while still achieving required road conditions for public safety," said a statement from Christopher Paquette, the city's program manager of operational and research projects. "There are multiple factors that contribute to the amount of salt and calcium chloride used each season, including the amount of snowfall, freezing rain, freeze-thaw cycles, and the duration of each of these weather events. Ottawa experiences an average of 77 freeze-thaw cycles over the winter season (five-year average)."

Paquette says the city is piloting three new sidewalk machine salt controllers this winter that will allow crews to use specific application rates in equipment and accurately monitor salt usage.